Clinometer.



A. R. MILLER,

CLLNOMETER.

MPLICATIUN man Dc.27,1917.

Lw, PatentedAug. 27, w18.

ARCHIBALD 1t.I MILLER, ,OF HELENSBURGH, SCOTLAND.

CLINOMETR.

Specification of Letters Patent. Patented Allg; 27, 1918.

Applicationaiea December 2v, 1917. sel-rs1 No. 209,067.

To all 'whomvz't may concern:

Bev it known that I, AnoHiBALD RUSSELL MILLER, a subject of the King ofthe United Kingdom of Great Britain and Ireland, and residing atHelensburgh, Dumbartonshire.l Scotland, have invented a certain new anduseful Improvement in' Clinometers, of which the following is aspecification.

The subject of this inventionis an instrument applicable to air-craftand seaecraft or as a clinometer generally, but designed primarily forindicating visually to the pilot or observer on an aeroplane or the likedepar ture from normal level of the aeroplane or the like at anyinstant.

An instrument according to the invention comprises a closed box orcasing containing liquid, and preferably mounted to swivel in bearingsin a bracket attachable, say, to any convenient part of the aeroplanewithin the field of vision of the pilot or of the observer, said boxcontaining a buoyant compartment or chamber which contains, say,atmospheric air or gas, and mounted on axis of rotation coaxial withsuch cylinder.' in such manner that the buoyant compartment willmaintain a uniform position of level irrespective of anyangularmovementsy of the box. By means of a dial or pointer applied or attachedto the compartment, and observablethrough a circular glazed opening inthe box, the normal position of level of the aeroplane or the like canbe ascertained at any instant. Suitable marks or scale divisions may beapplied around the said glazed opening in the box, by comparison ofwhich with the dial or pointer of the buoyant compartment variation ordeparture from normal level of the aeroplane or the like can be visuallymeasured.

The box is desirably suspended so as always to maintain an approximatevertical position -at'right angles to the line of the suspension points.l

The liquid contained within the box is preferably one having a lowfreezing point, such as an alcoholor a mixture of an alcohol andglycerin.

The invention is illustrated by way of example in the accompanyingdrawings in which Figure l is a front elevation and Fig. 2 a verticalsection at right angles thereto, the support not being shown.

As shown, A denotes the outer box or casing having a glazed front B anda lling aperture adaptedto be closed by a screw cap.l I

or plug C after admission V,of liquid into the box A, Visible throughthe glazed opening" and concentric therewith, is a fixed circular scaleK. D, D denote two disks which, g

in conjunction with. yan intermediate semis cylindrical section, formahermeticallyk sealed compartment F containing air or gas, said disks andcompartment being of light material and having axially disposed pivotsE, E working in bearings as shown. The buoyant compartment constitutesan indi;- Cator, the disk face of which nearest the glazed front B ispreferably colored white and inscribed with a straight black line orpointer H disposed vhorizontally and serving to denote normal level; ora vertical pointer or indicating mark may be provided on the front diskD such as shown at the bottom of the arrow mark J on the scale.

Fixed withinthe box A is a cylindrical shell L having two smallperforations M to permit passage of liquid. The shell L is intended tobe completely submerged by the liquid to prevent any surface action of'the liquid disturbing the buoyant compartment, and is spaced from thewall of the box A to afford a space which allows for expansion andcontraction of the liquid and air, withf out interference with thevolume of liquid in Vby means of the bracket or other attachment; in aposition to record either (l) transverse or (2) longitudinal level, anddepartures therefrom; one instrument being required for each suchpurpose. The bracket, or other attachment, being fixed to the body ofthe aeroplane, will move with the latter, and the box must, therefore,conformto any motion which is at right angles to the axis of the diskindicator.

The disk indicator, being on a free axis, will, by reason of the upwardthrust ofthe Vliquid on the air compartment, retain a normal levelposition, irrespective of angular movements of the box. Thus, anydeiection from normal level will be visible on com parison Oi' theinscribed line or pointer of the disk indicator With the circular scale.

The effect of centrifugal force is reduced to a minimum, error arisingtherefrom being very slight and immaterial for practical pur- OSGS.

The disk indicator will not be affected by extraneous vibration orshock, owing to the buoyant tension thereon, and also to the cushioningaction of the liquid.

VThe interior of the box is entirely smooth, so, that frictional dragand resistance are reduced to a minimum, and any such effect will beabsorbed and nullied by the extent of the space occupied by the liquidin contact with the moving surfaces.

The pointer and scale may be luminous so as to be visible in the dark.

Vhat I claim is:

The herein described clinometer comprising, in combination, a boxcontaining liquid, a buoyant hernietically sealed compartment of theform of a segment. of a cylinder mounted upon and free to rotate Withinsaid box on an axis coincident with that of said cylinder, saidcompartment being completely submerged in liquid contained Within saidbox, said compartment and said box provided with coperating indicatingdevices,

and means for protecting said compartment Copies of this patent may beobtained for ve cents each,` by addressing` the Commissioner of Patents.Washington, D. C."

